Related papers: The Seesaw Mechanism in Quark-Lepton Complementari…
We present a new parametrization of the minimal seesaw model, expressing the heavy-singlet neutrino Dirac Yukawa couplings $(Y_\nu)_{ij}$ and Majorana masses $M_{N_i}$ in terms of effective light-neutrino observables and an auxiliary…
We show that the observed structure of quark and lepton masses and mixing angles can arise entirely geometrically from superstring constructions, at the renormalizable level. The model we consider is a $Z_3$ orbifold compactification of…
We suggest an approach to explain the observed pattern of the neutrino masses and mixing which employs the weakly broken quark-lepton symmetry and does not require introduction of an ad hoc symmetry of the neutrino sector. The mass matrices…
We investigate a seesaw type mass matrix $M_f\simeq m_L M_F^{-1} m_R$ for quarks and leptons, $f$, under the assumptions that the matrices $m_L$ and $m_R$ have common structures for the quarks and leptons, and that the matrix $M_F$…
The current neutrino experiments provide an opportunity for testing the inverse see-saw mechanism through charged lepton flavor violating processes and neutrinoless double beta decay. Motivated by this, in this paper we study the…
Approximate flavor symmetries in the quark sector have been used as a handle on physics beyond the Standard Model. Due to the great interest in neutrino masses and mixings and the wealth of existing and proposed neutrino experiments it is…
We consider the supersymmetric seesaw mechanism induced by the exchange of heavy SU(2)_W triplet states, rather than `right-handed' neutrino singlets, to generate neutrino masses. We show that in this scenario the neutrino flavour structure…
In contrast to the original type I seesaw mechanism that requires right-handed Majorana neutrinos at energies much higher than the electroweak scale, the so-called low scale seesaw models allow lighter masses for the additional neutrinos.…
Assuming the same form of all mass matrices as motivated by quark-lepton symmetry, we discuss conditions under which bi-large mixing in the lepton sector can be obtained with a minimal amount of fine tuning requirements for possible models.…
Assuming Majorana nature of neutrinos, a general expression for the charged lepton corrections to scaling neutrino mixing has been obtained in the context of three flavor neutrino oscillations. Non-zero value of the reactor mixing angle is…
A non-minimal approximation for effective masses of light and heavy neutrinos in the framework of a type-I seesaw mechanism with three generations of sterile Majorana neutrinos which recover the symmetry between quarks and leptons is…
Pursuing a bottom-up approach to explore which flavor symmetry could serve as an explanation of the observed fermion masses and mixings, we discuss an extension of the standard model (SM) where the flavor structure for both quarks and…
We examine minimal seesaw mechanism in which the masses of light neutrinos are described with tri/bi-maximal mixing in the basis where the charged-lepton Yukawa matrix and heavy Majorana neutrino mass matrix are diagonal. We search for all…
In a seesaw mass matrix model M_f = m_L M_F^{-1} m_R^\dagger with a universal structure of m_L \propto m_R, as the origin of m_L (m_R) for quarks and eptons, flavor-triplet Higgs scalars whose vacuum expectation values v_i are proportional…
An extension of the Standard Model (SM) based on the non-Abelian discrete group $\Delta(27)$ is considered. The $\Delta(27)$ flavour symmetry is spontaneously broken only by gauge singlet scalar fields, therefore our model is free from any…
We discuss the possibility of flavor symmetries to explain the pattern of charged lepton and neutrino masses and mixing angles. We emphasize what are the obstacles for the generation of an almost maximal atmospheric mixing and what are the…
The recent experimental measurements of the solar neutrino mixing angle $\theta_{sol}$ and the Cabibbo mixing angle $\theta_C$ reveal a surprising relation, $ \theta_{sol}+\theta_C \simeq \frac{\pi}{4}$. We note that the lepton mixing…
We propose two Type-II seesaw scenarios for the neutrino mass matrix in the left-right symmetric model, in which the Higgs triplet Yukawa coupling matrix takes the appealing Friedberg-Lee texture. We show that the nearly tri-bimaximal…
We propose a left-right model of quarks and leptons based on the gauge group $SU(3)_C \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$, where the scalar sector consists of only two doublets: (1,2,1,1) and (1,1,2,1). As a result, any fermion…
We propose a renormalizable $T'$ flavor model based on the $SU(3)_C\times SU(3)_L\times U(1)_X\times U(1)_{\mathcal{L}}$ gauge symmetry, consistent with the observed pattern of lepton masses and mixings. The small masses of the light active…